The present invention relates to a ground piece of an electric connector, and especially to a ground piece used to a connector of a universal serial bus with double seat.
With the improvement of computer science, the connectors of universal series bus (USB) are necessary elements. In general, they are used in interfaces for connecting a keyboard or a mouse to a main frame. The double seat connector is modified from the single seat connector and is employed to be connected with two connectors at the same time. Moreover, the double seat connectors has various applications instead of merely being used in a keyboard or a mouse. In the prior art, a double seat stacked connector 2a is not connected with the housing 1a of the mainframe. As illustrated in FIG. 1, only a retaining piece 11a is installed on the back plate of the mainframe. The retaining piece 11a serves to position all the connectors of interfaces. The retaining piece is made according to the specification for designing a connector. The most original way is to be formed with a square hole 12a. The inner diameter of the square hole 12a is slightly smaller than the size of the periphery of a connector. A retaining strip 13a is transversally installed in the middle portion of the square hole 12a of the retaining piece 11a. Initially, the retaining strip 13a has an effect of positioning so that the connector 2a installed in the housing 1a can not be pulled out from the square hole 12a. While a plug type connector matched the housing must pass through the square hole 12a of the mainframe retaining piece 11a. The plug type connector is inserted into a receptacle type connector so that the matched connector can be assembled and matched. Since the connector has double seats, large pulling and inserting forces generates. In order to consider the electromagnetic interference, the interference electromagnetic wave must be cancelled. Therefore, a metal isolating piece must be placed at a middle portion of a double seat connector as a spacer for reducing the interference therebetween.
As shown in FIG. 1, a prior art is illustrated. A protrusion is formed for being connected to the retaining strip 13a of the retaining piece, so that the electromagnetic interference generated in two connecting modules is directly transferred to the housing 1a. The connector 2a has an insulating seat 22a and a metal casing 21a. The insulating seat 22a has a terminal set at an upper half and a terminal set at a lower half (not shown). The insulating seat 22a is inserted into the metal casing 21a. A positioning structure is positioned between the insulating seat 22a and the metal casing 21a. The positioning structure has no relation to the present invention and thus, the detail will not be described further. A transverse spacer extending forwards is installed at a middle portion of the insulating seat 22a (referring to FIG. 3). By the spacer, the insulating seat 22a is divided into an upper chamber 23 at the upper half and a lower chamber 24a at the lower half. Each chamber is provided with a space for combining with a matched connector. A metal clip piece 25a is inserted into the insulating seat 22a. The metal clip piece 25a has a  shape. Two ends of the metal clip piece 25a are inserted into the metal casing 21a. Meanwhile, two lateral sides of the metal clip piece 25a are inserted with respective hooks 26a for being buckled to the retaining hole 27a of the housing 21a. The inserting edges of the metal clip piece 25a each have a hook (not shown) for being inserted into the buckling groove (not shown) of the insulating seat.
A transverse portion from the folded two ends of the clamping piece 25a covers the outer surface of the spacer. Namely, two ends of the clamping piece are adhered to the upper and lower two lateral surfaces of the spacer. Therefore, the aforesaid positioning structure serves to fix the clamping piece 25a to the housing 21a and therefore, a pair of outer folded pieces 28a which are opposite and punched outwards are installed on the transverse portion of the clamping piece 25a. Therefore, the outer folding pieces 28a are in contact with the retaining piece 13a so that the outer folding piece 28a has an effect of grounding. However, since the outer folded piece 28a only contacts the retaining piece 13a by a tip portion thereof, as it is used for a long time, it will fatigue and deformed by pressure so that the outer folded piece loses the function of grounding.
Accordingly, the primary object of the present invention is to provide a grounding device of an electric connector, ground pieces more flexibly and steadily are used extra auxiliary ground structure. Thereby, the resisting portion obliquely extended and having a plane shape is in contact with a housing so that the ground piece is connected to the housing in a surface contact way. The contact area is sufficient. Consequently, the ground piece is substantially guided and can be used for a longer time with fatigue in elasticity. A steady combination is formed with the housing. Even a matched connector is in a pulling away condition, it can acquire an inverse holding force so that the connector can be protected well and provides a well application.
To achieve the object, the present invention provides a grounding device of an electric connector is disclosed. An insulating seat is installed with a plurality of terminals and is installed with a spacer. A housing encloses the insulating seat and made of metal material. A clamping piece has a  shape and is made of metal material. The clamping piece is positioned to the spacer and the housing. Two sides of a meddle connecting piece of the clamping piece each are protruded with a combining portion. A pair of ground pieces has a T shape with one end being a retainer and another two ends being resisting portions. The retainer is inserted into the middle connecting piece of the clamping piece. A punched buckling portion is formed on the retainer near the resisting portion. Thereby, the combining portion is inserted into a hollow chamber in the buckling portion and is pressed and thus fixed therein. Between the buckling portion of the retainer and the resisting portion is formed with an oblique extended bending portion. The resisting portion of the ground piece is parallel to the middle connecting piece of the clamping piece.
The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing.